Modern drills used in forming boreholes in the face of underground mine passages, sometimes referred to as “face” drills, typically include a boom carrying a feed beam supporting a drill head as it reciprocates. To facilitate movement of the drill head in a smooth and efficient manner, replaceable pads formed of a wear resistant, yet lubricious material (e.g., polyurethane) are used for mounting the drill head or other related components (e.g., centralizers) to the feed beam. This not only facilitates the desirable smooth movement, but also maximizes the service life and reduces the maintenance requirements, which in turn decreases operating cost and increases yield.
Many past proposals exist for coupling the wear pads with the supports (or “gibs”) for the drill head or like component to the feed beam. One such arrangement requires two wear pads, one positioned along each side of the feed beam associated with a single drilling component. Each wear pad includes a tenon portion, such as a dovetail, corresponding to an elongated, open-ended channel or mortise formed in each of a corresponding pair of supports. Since the dimensions of the dovetail must necessarily be smaller than those of the channel to permit insertion in the longitudinal direction, retainers extending through oblique holes hold the wear pad in place during the rigors of drilling.
U.S. Pat. No. 5,704,716 to Jantunen describes a subsequent, but similar approach and is incorporated herein by reference. The '716 patent discloses a support structure, referred to as a “slide frame,” located along each side of a feeding beam. A single channel in each slide frame receives a dovetail formed along a backside of a polyurethane cast slide member. Bolts extend through the slide frames and prevent the slide from moving in the longitudinal direction.
This type of arrangement only allows for insertion of the slide member in a longitudinal direction. Hence, the dimensions of the dovetail must necessarily be smaller than those of the corresponding channel. Otherwise, the allegedly desirable mode of insertion solely in the longitudinal direction could not result.
The need for deliberately undersizing the dovetail or oversizing the corresponding channel to facilitate insertion in a longitudinal direction creates problems in certain drilling applications. For instance, this undersizing or oversizing creates a gap that allows for possible misalignment of the drill head or other supported components. While retainers used in the prior art approaches at least initially help to prevent such longitudinal movement, the possibility of back and forth movement against them remains. Over time, this can lead to tearing or cracking of the wear pad or slide. At a minimum, this creates a need for early and frequent inspection, and if left unchecked could result in a catastrophic failure.
Accordingly, there is a need for an improved mounting arrangement for a drill head or other component associated with a feed beam in a face drill. The arrangement would permit the insertion of a wear pad including a tenon, such as a dovetail, in a corresponding matching channel or mortise in a direction other than the longitudinal direction. This would potentially allow for oversizing the portion of the wear pad received in the channel to ensure that it remains held securely in place and resists tearing or cracking during the rigors of drilling.